Strathcona Beekeepers' Library: Winter Preparation for Vancouver Beekeepers

    It's August and time for Vancouver beekeepers to prepare for winter. Actually winter preparation is an ongoing task (Beekeeping Calendar for B.C.). The main reasons our bees die over the winter is starvation, colonies suffering from parasitic mite syndrome, too few bees to heat the cluster and moisture. I complete my winter hive setup by the middle of October. Much of what you do in preparation depends on your management style of beekeeping (virtually nothing for the extreme natural beekeeper to intense management for others). This is a revised post from last year and are just a few suggestions based on my experience keeping bees in Vancouver.

Food
     To address the food issue you will need at least 10 deep frames or 12+ medium frames of honey (65 lbs or 30 kgs) for an average sized colony to survive the winter. In our specific location (Strathcona) we still have a strong availability of nectar and pollen with many different plant species still in flower in our 4 acre garden and the surrounding area. Due to global warming plants in Vancouver can begin to flower 2-3 weeks earlier than in the past so our forage shortage begins in mid September. The problem occurs when the temperatures are still warm and dry enough from mid September through October for the colony to stay active. An active colony without a natural food source will consume much of the winter food supply. I'm fortunate this year to have a good supply of honey frames from my stronger hives that I can share with my weaker hives. This is why I prefer to wait til October to extract honey when I know the state of my winter supply. Some beekeepers have started feeding 2 to 1 syrup to their hives now because their honey reserves are low. This is a personal decision based on your style of beekeeping and your location. I usually like to reserve my feeding to emergency late winter feeding. An issue with syrup feeding this time of year is making sure most of the syrup the bees store gets capped. The uncapped syrup will become a source of winter moisture and mold.
     I've identified our main foraging shortage to occur from mid September to mid October so to address this issue I have separated the root balls of common Asian Asters for planting and transplanted the invasive Canadian Goldenrod (Aster). When mature the common Asian Aster becomes a 1.5 by 1.5 metre (4 by 4 foot) bush with hundreds of flowers and can bloom well into October. We have about a few hundred autumn flowering variety Asters in our 4 acre garden. Other late bloomers in our garden are Japanese Anemone, Mint, Autumn Joy Sedum, Scarlet Runner Bean, Jersulam Artichoke, and the invasive Japanese Knotweed (Nectar Plants of British Columbia). A mixed diet is essential for the girls so some other late blooming plants are Caryopteris 'Dark Knight' (Blue Mist Spirea), Dahlia, Hardy Fushia, Seven Sons flower (Autumn Lilac), Impatiens omeianan, Camellia sinensis (Hardy tea bush) and Osmanthus fragrans (Fragrant Olive) (Nutritional Value of Bee Collected Pollens and Pollen Sources). I will avoid the temptation to plant the invasive late blooming ivy and Himalayan Balsam.

Goldenrod

Aster

It's good at this point to make sure you have your emergency winter feeders ready if you plan to use them. A major cause of colony death is late winter starvation (February - April) which can be solved by the use of an emergency winter feeder (Candy Board).

Candyboard

They're easy to build with 1x2's and quarter inch wire mesh and can be a colony lifesaver. You can quickly check on the feeders through the late winter to gauge the status of the food supply. Some beekeepers begin feeding in August. This article "Feeding Bees in Winter" describes the different methods of feeding at different temperatures. The girls will take a 2 to 1 syrup down to about 12 celsius (53 fahrenheit) after which they find it too difficult to dehydrate for storage. Some beekeepers will feed syrup baggies on top of the frames in colder temperatures on the theory that heat from the cluster warms the syrup. I've not tried this. In the Greater Vancouver area there are very big differences in winter food requirements based on available foraging days and available forage. Because of the effect of the North Shore Mountains precipitation varies from 150+ inches (380 centimeters) annually at the upper altitudes of the mountains to 30 inches (75 centimeters) along the U.S. border. This effect reduces precipitation and increases hours of sunlight as you move southward. The graph below divides Greater Vancouver into 9 zones with 9 being the upper altitudes of the North Shore Mountains and 1 being the southern region along the U.S. border (Greater Vancouver Precipitation). As the crow flies this is a distance of less than 30 kilometers or 20 miles.

Though active at lower temperatures I have found high population foraging in our apiary at 12 degrees celsius (53 fahrenheit) in March (Willow trees, Forsythia, Flowering Cherry).

This means more flyable, foraging weather the further south you live and the more active the colony with the additional needed sunshine warming the hive and bees. I have observed the activity of the bees throughout the lower mainland to be directly linked to the number of hours of sunlight on the hives. Conclusion, for optimum colony health move to a southern suburb like Tsawwassen, Ladner, White Rock or Abbotsford or maximize the sun exposure on your hives (South to southeast exposure with minimal shade). We moved our apiary because it was surrounded by fast growing Black Locust, Willow and Cottonwood trees (Great pollen and nectar sources).
Also effecting hive performance is available forage which can vary according to whether you are in a rural agricultural or urban setting. The rural, agricultural areas in Surrey, Delta and the Fraser Valley tend to have extreme honey and brood production during crop blossoms but can suffer in the off season while the urban areas tend to have a more consistent food source availability throughout the foraging period (March - November) due to urban landscaping and irrigation. We're fortunate to have 7 cultivated acres in our 2 combined community gardens surrounded by fields of clover and flowering trees. While it varies by region, because of the reasons discussed above (weather and available forage) and the size of the colony we need on average a minimum of 10 deep or 12 medium frames of honey (65 lbs or 30 kilograms) to over winter. The honey frames should be positioned on both sides of the cluster in the bottom box and above the cluster in the second super (super = hive box). If the cluster is in an upper box it's recommended to switch the box to the bottom in preparation for winter. In the spring you can reverse that process as the girls will have worked their way up to upper part of the second box.

Winter cluster at the end of winter

For a Kenyan Top Bar put the cluster at one end and the honey frames next to the cluster. I've always run all deep supers in my Langstroth hives because universal boxes and frames are easier to manage. I can add honey frames from my third or fourth box to the brood boxes to over winter. Many new beekeepers and some old are moving towards all medium boxes because of the lighter weight. This makes sense as a deep box of honey can weigh 80 lbs (36 kgs).
      All beekeepers have plus and negative food accumulation months and generally April 1 to Oct 1 are positive food accumulation months for us in the Strathcona area of Vancouver. March and October can be neutral but are usually negative depending on the available foraging days (weather). November through February are winter cluster, negative food accumulation months.

Pest and Disease Control
     The biggest problem I see with new beekeepers is not planning ahead. In our beekeeping coop new beekeepers are always rushing around for needed hive boxes and frames, feeders, robber screens, quilts …. The best advice I could give new beekeepers is to plan 2 months ahead of where you are at. Pest and disease identification and control should be an ongoing process and if you are beginning now it may be too late. Evidence of chalk brood or nosema would indicate a weak colony (Honey Bee Diseases and Parasites). Increased ventilation and removal of old comb can be done to combat the chalk brood and a pollen patty/fumagillin mixture may help combat the nosema. Mite counts throughout the year and subsequent treatments should let you know whether you have a major issue. Mite treatments like formic acid can continue into October as long as there is a day time high temp of 10c and oxalic acid is usually done in December when there is little to no brood present. A mistake made by many beekeepers is to treat in August and with a large, healthy colony assume everything is fine. Continue mite tests and treatment through September. A reduced screened entrance using eighth inch hardware cloth can be used to allow for needed ventilation during formic acid treatments while providing a more easily defended (against wasps) reduced entrance. The video below "Getting Your Hives Ready for Winter" is a recorded webinar with Kim Flottum (Bee expert and editor of Bee Culture magazine) which does a very good job of discussing winter preparation for bee colonies focusing on year around mite control. Controlling mites goes a long way to controlling virus transmission and overall colony health.

Cold and Moisture
      The U.S. Bee Informed Survey of wintering hives (the only large scale North American winter survival survey) showed that only 3 conditions determined winter survival success and they were adequate food, strong colonies (equalization or combining hives) and ventilation (moisture reduction).

The survey is extensive and includes the results for geographic region, all types of pest and disease management, feeding and winter preparation. The Bee Informed Survey 2016 - 2017

Wrapping and insulation showed no benefit but I think that depends on where you live. If you live in cold northern climates like Winterpeg either you wrap and insulate or you bring the girls inside. 40 below is 40 below. Insulation is not necessary in Vancouver and can be counter productive by keeping the heat out and preventing the hive from warming up. Some local beekeepers wrap their hives with black roofing paper to prevent wind penetration and to help absorb the heat (Black objects absorb more heat). The argument against this is that the girls take care of any wind penetration with use of propolis and do we want a warmer hive in the winter? Warmer means more active bees and more food consumption. For us wrapping in March may be a good option as we have lots of blossoms (Willow, forsythia, flowering cherry, bulbs ...) but marginal foraging temperatures. Wrapping would warm the hives and get the girls flying earlier in the day increasing their pollen and nectar intake and stimulate egg laying.

Temperature difference on black and white surface

Wintering your bees is like real estate value in that the 3 most important considerations are location, location and location. Location dictates the methods you will use to protect your bees from the elements. Windbreaks are essential in some areas where there are cold, winter winds, especially for rooftop beekeepers. In winter Vancouver has a predominant, low pressure weather pattern with winds from the southeast that bring with it fairly constant cool, wet weather. We have only a few snow falls per year and a few weeks of freezing temperatures. Therefore moisture, not cold is our biggest issue. The moisture is created when warm air created by the cluster of bees rises and contacts the cold inner cover creating cold condensation which drips onto the cluster. There are a lot of different methods to reduce moisture in the hive like tilting the hive forward by putting a 2x4 under the back of the hive to allow the moisture to run down the front of the hive and not on the cluster. Another option is an Insulated Moisture Quilt placed above the hive boxes to reduce cold condensation dripping on the winter cluster.

The bee hive in winter without any form of moisture reduction

Insulated Moisture Quilt

The heat produced by the cluster rises to contact the warmer insulated cover producing less condensation, which then drips onto the wood chips (not the bees) which are dried by the vent holes. They are easy to make out of scrap material and the link above provides detailed building instructions. During winter you must have an upper entrance in your Langstroth hive for ventilation and because dead bees can block the lower entrance. I presently have my upper entrance covered with eighth inch hardware cloth to keep out robber bees and wasps. I will remove this once those threats have passed. For moisture reduction in a Kenyan Top Bar Hive beekeepers can use an insulated moisture quilt, carpet over the top bars (Bill Stagg's method) or reflective insulation (Sam Comfort's method). Whether you leave your screened bottom board open or not (for increased ventilation) is debatable but if left open you must block the drafts from blowing under the hive. I put the mite test board in to block the winter winds but have friends who do not and successfully overwinter their bees. One moisture issue is that if you feed syrup to your bees in September and October some of the stored syrup may not be capped before the arrival of winter and it may ferment and mold and increase the moisture within the hive.
In Vancouver we get at least 2 major storms a year of 80+ km winds (50 miles per hr). For this reason and the presence of skunks and racoons we use cinder blocks on our hives to prevent the outer cover from blowing off or being removed and have positioned the hives to have a natural wind break (berm to the south). A wind break is particularly important for roof top beekeepers. Though not necessary some of us use pieces of plexiglass extending 4+ inches over our outer covers to provide additional weather protection and extend the life of our beekeeping equipment.

Winter Hive

Wasps
With the decrease in available forage robbing and wasp attacks become a real concern starting in August so guard bees will become more defensive and in the wild the colony may reduce the size of the entrance with propolis and wax. The beekeeper can assist by reducing the entrance to as small as 1.5 centimeters or a half inch to make it easier to defend. In Vancouver wasps have been more aggressive, longer into the winter over the last few years. I received a swarm call last year in December. There had been a few hard frosts so out of interest (knowing it wasn't a swarm) I went to see a very active paper yellowjacket nest in an unheated crawl space. The Yellowjacket wasps and Bald Faced Hornets have been aggressive in our apiary for about 4 weeks, attempting to enter hives and picking off stray bees at the entrance. I have reduced the bottom entrance of my hives to between a half inch (1.5 cm) for weaker colonies to 3 inches for stronger colonies and screened off the upper entrance (eigth inch hardware cloth). This blocks potential wasp intrusion and robbing by other bees if you are feeding and still allows ventilation. The girls are better able to defend the reduced single entrance. Wasps will stay active at cooler temperatures than your bees so when the girls are in cluster the wasps may enter the hive. I don't indiscriminately kill wasps (I've identified 9 different types in our garden including recently a parasitic wasp in my blue mason and leaf cutter bee cocoons) but have found them increasingly aggressive towards our colonies for a longer period of time in the fall (last year until December). I've found the pheremone lure variety to be very effective on our greatest threat which are the common Yellowjacket wasps (does not attract Bald Faced Hornets). This lure trap can also be used in the spring to kill the emerging wasp queens. The Rescue brand lure variety works well.

Wasp trap

You can also make your own wasp trap. Here is a study from the University of Athens showing the effectiveness of 3 different types of traps (Wasp Traps). Maybe the easiest and most popular is the pop bottle trap. We have a number of these out now with a 50/50 mixture of sugar and water and a capfull of vinegar poured in the entrance to keep the bees away. They have worked very well but you need to add a capfull of vinegar occasionally to dissuade the bees. Here is a study from the University of California on the effectiveness of different baits (Baits for the Control of Yellowjackets). I've not had much success with fish or meat baits later in the summer. These protein baits are successful earlier in the season when the wasps are feeding their brood. Wasps prefer a sugar and water bait at this time of year. For more information on wasps go to the Wasp section of our Beekeeping Library.

If wasp attacks or robbing persists you can use a robber screen which are easy to make.

Equalization or Combining Colonies
It is recommended that new beekeepers have 2 hives rather than 1 because inevitably one will be stronger than the other. This allows you to strengthen the weaker hive with bees from the stronger colony (Equalization of Bee Colonies Strength by Khalil Hamdan) or to split the stronger hive if you lose the weaker colony. Though this can be done in the spring it can also be done in preparation for winter by adding 2-3 frames of bees and brood as needed and available every 3-4 weeks starting in July. If you find you have a weak colony now you can combine the colony with a stronger one using the newspaper method (Uniting Honey Bees by David Cushman). Although some will insist it imperative to kill the weaker queen others like the late, great David Cushman suggest that it is not necessary: "Many texts will tell you to kill the least desirable queen in one of the two groups to be united, but I find it is often prudent to leave both queens, so that the bees can make the choice, in most cases the younger and fitter queen remains, but there may be subtle things in a queen's make up that the bees are better able to make choices about rather than the beekeeper (David Cushman)." Some beekeepers (not me) like to requeen as part of their winter preparation to make sure they have young, active queens the following spring. In October most beekeepers reduce their Langstroth hives to 2 deep supers and Kenyan Top Bar hives are reduced by moving your follower board or your false backs forward (Winterizing your Top Bar Hive). Queen excluders should be removed so the queen can move with the cluster as it moves upward.

The newspaper method of combining hives

Mice
Though still mild it's time to think of mice which like to winter in the hives. There are a hundred different varieties of mouse proof entrances from quarter inch screened mesh, drilled metal sheet to simple nails minimizing the entrance. The mice can get through a fairly small area and will chew through wood. I use a simple wood entrance reducer with a nail reducing the entrance to just over the width of a bee. This allows for the removal of dead bees which the girls do as part of winter house cleaning. If you find the mice chewing on the entrance reducer you can wrap it in wire mesh. Here is an easy step by step guide to making a mouse guard from Brooksfield Farm just south of us near Mt. Baker.